1 error: `derive` cannot be used on items with type macros
2 --> $DIR/issue-32950.rs:5:5
4 LL | concat_idents!(Foo, Bar)
5 | ^^^^^^^^^^^^^^^^^^^^^^^^
7 error[E0412]: cannot find type `FooBar` in this scope
8 --> $DIR/issue-32950.rs:5:5
10 LL | concat_idents!(Foo, Bar)
11 | ^^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
13 = note: this error originates in the macro `concat_idents` (in Nightly builds, run with -Z macro-backtrace for more info)
15 error: aborting due to 2 previous errors
17 For more information about this error, try `rustc --explain E0412`.